Winding construction for high efficiency machine

ABSTRACT

A permanent magnet motor, generator or the like that is constructed with a concentrated winding and edge form wound stator coils. This achieves less eddy current losses in the windings as well as a much higher power density than conventional techniques.

BACKGROUND OF THE INVENTION

Rotary electric machines including electric motors, generators, and thelike have employed various types of stator windings. The most commonstator winding type is a distributed winding. One type of which is aninteger-slot winding wherein the number of slots per pole per phase isan integer. An example of this is a 4 pole 12 slot, 3 phase motor. Thenumber of slots per pole per phase is 1 and therefore an integer. Thesewindings typically require some relatively complex end turns to wirethem properly.

Another type of distributed winding is a fractional-slot winding. Whenthe number of slots per pole per phase is a fraction greater than one,this is called a fractional-slot winding. This also has complicated endturns and has the disadvantage of being less efficient. It is sometimesused to smooth out torque ripple or for other specific applications.

Another type of winding is a concentrated winding when the number ofslots per pole per phase is a fraction less than one. These can also becalled a non-overlapping concentrated winding. They have thedisadvantage of decreasing the inherent efficiency of the device, butmake the end turns very simple and can facilitate other advantages. Anexample of a concentrated winding would be an 8 pole, 9 slot, 3 phasemachine. The number of slots per pole per phase is 0.375 in this case.The fundamental power from this configuration is reduced by 5.5%.Concentrated windings can be single layer or double layer designs.Single layer designs have windings that are wound only on alternatingstator teeth and only apply where there is an even number of statorslots/teeth. Double layer designs have coils wound on every statortooth. In this configuration, there is a coil that surrounds each of theteeth on the stator and there are the same number of coils as slots.Further, each slot has half of one coil and half of another coil goingthrough the slot and the end turns are very short. Ideally, the endturns can be as short as the width of the stator tooth.

Double layer concentrated windings have the advantage of being a simplecoil wrapped around each tooth. For an external rotor configuration, andusing relatively open slots, this allows simple assembly of coils. Forthe more typical internal rotor configuration, assembly is a bittrickier because even with relatively open slots, the opening is smallerthan the slot. This is further complicated if the slot opening is madesmaller for motor performance reasons. A typical method of mitigatingthis issue is to make the teeth separate to either be able to 1) windthe wire directly on the tooth or 2) slide the winding on from theoutside. The first method is shown in U.S. Pat. No. 5,583,387 entitledSTATOR OF DYNAMOELECTRIC MACHINE incorporated herein by reference. Thesecond method is shown in U.S. Pat. No. 4,712,035 entitled SALIENT POLECORE AND SALIENT POLE ELECTRONICALLY COMMUTATED MOTOR also incorporatedherein by reference although it is shown as an external rotorconfiguration. Both methods are shown as conventional in U.S. Pat. No.8,129,880 entitled CONCENTRATED WINDING MACHINE WITH MAGNETIC SLOTWEDGES, incorporated herein by reference. The challenge with any statorlamination design that has separate teeth is to secure the teethstructurally so they do not move or break. Even small movements of theteeth can cause acoustic noise. A second challenge is to configure thejoint in such a way to not significantly disturb the magnetic fluxtraveling through the laminations. If the joint could be made with zeroclearance this would not be a problem, but with real manufacturingtolerances and features required for attachment, this is a majorconsideration.

Rotary electric machines including electric motors, generators, and thelike have employed various methods of constructing stator windings. Somemethods are applicable to only certain types of stator windings.

One common method is random winding. This method can use rectangular orround wire, but typically uses round wire. Here the windings are placedby the winding machine with the only requirement that they be located inthe correct slot. This is the easiest method of stator winding, butresults in the lowest amount of conductor in the slot and therefore thelowest efficiency. This type method can be used with any type of statorwinding including concentrated windings.

Another common method is traditional form winding. This method typicallyuses rectangular wire with mica tape located between conductors toseparate any conductors that are significantly different in voltage.This insures a robust winding for higher voltage machines or machinesthat are prone to partial discharge. This is the most labor-intensivetype of winding and is typically used in machines that are less costsensitive. This type method can be used with any type of stator windingbut is typically used for distributed windings.

One winding type that is not typical in motors, is used in certain typesof transformers, chokes, and inductors is bobbin layer winding. Thistype of winding places conductors in exact locations for very accuratestacking of wires. This can achieve a high amount of conductors in asmall area for high efficiency. This is not typically used fordistributed windings because you are not able to bobbin wind a coil andthen insert it into a stator assembly. This is possible withconcentrated windings that have removable teeth. The most common wire touse is round wire but it is possible to use square or rectangular wire.Layer winding with rectangular wire is typically laid flat and wound theeasy way. This facilitates simpler winding, but one disadvantage of thisis the eddy current losses due to slot leakage can be significantlyhigher. Also, orientation of the rectangular wire can have an impact onthermal performance and depends on the overall heat removal scheme.

Layer winding with rectangular wire can be done edge wound (wound thehard way.) This is shown in U.S. Pat. No. 4,446,393 entitledDYNAMOELECTRIC FIELD ASSEMBLY AND WINDING THEREFOR incorporated hereinby reference. In this patent a single layer of rectangular wire is usedin each slot and is edge wound. This patent used removable teeth and aninternal rotor. U.S. patent application serial number 2010/0066198 filedMar. 18, 2010 entitled INSERTION OF PRE-FABRICATED CONCENTRATED WINDINGSINTO STATOR SLOTS incorporated herein by reference also shows a singlelayer of rectangular wire but does not use removable teeth. Edge woundcoils can have significantly lower eddy current losses in the wires. Thecooling may be better or worse depending on the overall cooling scheme.

Rotary electric machines including electric motors, generators, and thelike have employed various cooling methods including air cooling andliquid cooling. Liquid cooling is used to help make motors smaller andto remove the heat more efficiently.

The most common liquid cooling design uses a cooling jacket wrappedaround the outside of the stator assembly. This can be seen in U.S. Pat.No. 5,448,118 entitled LIQUID COOLED MOTOR AND ITS JACKET, includedherein by reference. In this design there is an aluminum extrusion thatsurrounds the outside of the stator and has passages for cooling fluidto pass through. This design cools the stator better than air, but islimited by i) the conductivity between the jacket and the stator, ii)the poor conductivity of the stator laminations, iii) the conductivityof the slot liners, and iv) the poor conductivity between the windingand the slot liners.

Another method that is commonly used is passing cooling through thestator laminations or into slots cut into the stator laminations. Eitherof these has similar disadvantages to the cooling jacket design.

Further, some techniques involve spraying fluid directly on the statoror submerging the stator. These have the disadvantage of either beingoverly complex or having the fluid cause drag between the rotor and thestator.

There are at least two techniques placing the cooling jacket through thewinding slot. One of these is forcing fluid down the center of aconductor. Typically the fluid in this case is a non-conductive oil.This has the disadvantage of requiring a special fluid and some complexmanufacturing methods to provide the fluid channel. Other techniquesplace a pipe or vessel down through the slot with cooling fluid in it.These typically also use non-conductive oil and have non-conductiveconnections to a manifold at their end. An example of this can be foundin U.S. Pat. No. 3,112,415 entitled CONTROL OF WINDING TEMPERATURES OFLIQUID COOLED GENERATORS, incorporated herein by reference.

Novel methods of cooling are also shown in other applications filed byMarvin et al U.S. patent application Ser. No. 13/548,199 entitled LIQUIDCOOLED HIGH EFFICIENCY PERMANENT MAGNET MACHINE WITH GLYCOL COOLING,Ser. No. 13/548,203 entitled LIQUID COOLED HIGH EFFICIENCY PERMANENTMAGNET MACHINE WITH IN SLOT GLYCOL COOLING, Ser. No. 13/548,207 entitledHIGH EFFICIENCY PERMANENT MAGNET MACHINE WITH CONCENTRATED WINDING ANDDOUBLE COILS, and Ser. No. 13/548,208 entitled HIGH EFFICIENCY PERMANENTMAGNET MACHINE WITH LAYER FORM WINDING all filed Jul. 13, 2012, allincorporated herein by reference.

SUMMARY OF THE INVENTION

The machine described herein incorporates several novel constructionmethods in its stator. It uses a concentrated winding with a novelapproach to secure its removable teeth. This method insures metal onmetal contact with real manufacturing tolerances. The preload caused bydeflected steel insures that this metal on metal contact maintainsitself in all loading conditions.

This design also uses Edge Form Wound windings which minimize eddycurrent losses in the windings. Further, the use of pre-insulated wire,novel cooling manifold location, and assembly loading insures a verygood thermal solution that allows much higher current density in theslot. This higher current density in the slot allows significantlyhigher overall power density of the rotating machine particularly inlarger machines and higher speed machines.

This edge winding solution needs a very sophisticated winding method toachieve accurate coils that can achieve high packing density and workreliably in demanding applications. The incorporation of a controlledwinding approach using pre-insulated wire is unique. Pre-insulated wirehas been used with simple pin-bending solutions, but this would notachieve the higher packing density or high yields in manufacturing.Further, in real applications, the wire size may need to get quite largeto accommodate the correct number of turns. This wire may get largerthan commonly available for pre-insulated wire and this larger wire willhave more eddy current losses in the wire due to slot leakage magneticflux. This design uses multiple in hand winding to solve these issues.

The machine described herein also includes novel in slot liquid coolingin a configuration that allows the use of conductive fluid such asethylene glycol. This configuration places the cooling manifold betweenthe winding and the stator laminations to give ideal cooling for thewinding as well as the stator laminations.

Further, this design uses metallic vessels that contain the liquidcooling medium for high reliability. These metallic vessels are brazedtogether into manifolds to efficiently direct the liquid to where theheat is generated.

The combination of these approaches leads to a very reliable, small,efficient, and low cost design.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a three dimensional view of the stator assembly,

FIG. 2 is a cross sectional view of the stator assembly of FIG. 1,

FIG. 3 is an enlarged detail sectional view of the stator assembly shownin FIG. 2,

FIG. 4 is cross sectional view of the stator assembly,

FIG. 5 is a detail view of the stator assembly shown in FIG. 4,

FIG. 6 is a detail view of the stator assembly shown in FIG. 5,

FIG. 7 is a cross sectional view showing motor/generator assembly,

FIG. 8 is two detail views of the motor/generator assembly shown in FIG.7,

FIG. 9 is a view of the inner coil from the stator assembly of FIG. 1and also shows a cross section of the rectangular wire and therectangular wire that has been shaped into a keystone shape,

FIG. 10 is a detail view of the stator assembly shown in FIG. 4,

FIG. 11 is a three dimensional view of an assembly with 4 coils and theinsulator of the stator assembly of FIG. 1,

FIG. 12 is a top view of the inner coil of FIG. 9,

FIG. 13 is a three dimensional view of the coils and insulator of FIG.11 with an added slot liner,

FIG. 14 is a three dimensional view of an edge winding machine beforewire is bent,

FIG. 15 is the edge winding machine of FIG. 14 after the wire is bent 90degrees,

FIG. 16 is a cross sectional view of the edge winding machine of FIG.15,

FIG. 17 is a three dimensional view of an edge winding machine winding 2wires in hand, and

FIG. 18 is a cross section view of the edge winding machine of FIG. 17.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring particularly to FIG. 1, a stator assembly 1 is showncontaining stator coils 2 and stator lamination teeth 3. Also shown is afluid manifold 4 for supplying coolant to the motor or generator.

FIG. 2 shows more detail on the stator assembly showing outer tube 6,outer laminations 5, and stator teeth 3. The stator shown in FIG. 2 hasa double layer concentrated winding since there is a winding aroundevery stator tooth. In addition, the stator winding is comprised of fourportions: innermost layer 8, second layer 9, third layer 10, and fourthlayer 11 as shown in FIG. 3. The four portions are separate and distinctfrom this being a double layer winding which refers to there being awinding around every stator tooth.

Each winding surrounds a cooling manifold with the upper portion 7 shownin FIG. 3 and the in slot portion 12 shown in FIG. 5. The coolingmanifold is shown with 8 holes in each side. Since this is an evennumber it facilitates a single sided manifold where in slot coolingvessels are connected only on one end of the machine. Since the numberof holes is divisible by four, it also facilitates making redundantcooling loops and a single sided manifold (two up and two down for eachof the two redundant loops.) These coolant loops can be connected totheir own pump and designed such that only one loop is necessary to keepthe machine cool.

This flow path is desirable since there are no electrically conductiveloops around stator teeth that are formed with the coolant. This isimportant because it allows the use of conductive fluids such as a waterand ethylene glycol mixture without sacrificing any performance.Further, it allows the use of metals to hold cooling fluid with brazedor soldered joints without causing any shorting paths. While usingsoldering or brazing, a preferable method of adding filler material iseither by using stamped foils inserted between components or by applyingpaste on one of the surfaces.

Having a soldered or brazed joint is important for the overallreliability of the system and is preferable to O-rings, hoses or otherinsulation systems. Fluid can pass through this passage in eitherdirection but preferably is in a cross flow configuration. These can bemanifolded from a single end and can be connected in parallel or inseries. A parallel configuration is the preferred method due to reducedfluid pressure drop with smaller passages.

The in-slot cooling manifold 12 as shown in FIG. 5 can be configuredwith a step 17 to facilitate better cooling with edge wound coils. It istypical that the available space in the slot is not rectangular and hasa more unique shape. By putting this step in the cooling manifold andmaking the height of the step equal to the thickness of the first layer,it allows a larger cooling surface without taking away from room forcopper wire in the slot. The tooth 3 as best shown in FIG. 5 is designedas a separate piece from the rest of the stator lamination. This is doneto allow the cooling manifolds and windings to be installed on the toothbefore insertion into the stator. This is desirable in many concentratedwinding designs but is particularly important on this design because theteeth 3 are designed to have a very small gap from each other. Furtherwhen using edge wound coils it is much easier to install with a straightin insertion that does not require deformation.

The tooth is preferably built with a bonded stack configuration whereall of the laminations are glued together. The tooth 3 mates with theouter lamination 5 along angled surfaces 19 a and 19 b as shown in FIG.5. The goal is to preload the tooth on these two angled surfaces suchthat the forces of the motor do not separate these surfaces. Toaccomplish this, a retention feature 20 is included to preload thesesurfaces. This retention feature 20 is shown in more detail in FIG. 6where there are two tabs 21 a and 21 b that are built as part of thisfeature. Wedges 22 a, 22 b, 23 a, and 23 b are driven in from the end todeform tabs 21 a and 21 b and preload surfaces 19 a and 19 b. Wedges arepreferably made of non-magnetic material to reduce eddy current losses.The best material choice would be an austenitic stainless steel, 300series stainless steel for example. To manufacture wedges easily and tofit the feature in the limited space available, wedges can be made outof sheet metal. This means that the width of the wedge pair 22 a and 23a for instance would be small compared to the combined thickness of thewedges as best shown in FIG. 6. The wedges in FIG. 6 show an examplewhere the combined thickness is approximately 3.7 times the width.

The location of this retention feature is important for magnetic fluxreasons. Teeth dimensions are preferably designed in such a way to notunacceptably saturate the iron but keep the tooth width as small aspossible. The magnetic flux travels from the tooth across surfaces 19 aand 19 b into the outer lamination portion 5. It is important to designthis retention feature out of the flux path which limits its location tooutside of the two cylinders shown by the two circles 18 a and 18 b inFIG. 5. All the cutouts in the outer lamination 5 to accommodateretention feature 20 are located outside of these two cylinders. Thesecylindrical exclusion volumes have a diameter equal to the width of thetooth and their axes are at the junction of the tooth side 3 a and 3 band the inside diameter of the outer lamination 5 a and 5 b. The angledsurfaces 19 a and 19 b are angled to accommodate this flux plusmechanically center the tooth when preload is applied through tabs 21 aand 21 b. Ideally the surfaces 19 a and 19 b have an angle between themof 100-170 degrees.

There are other features that may want to fall in the good sectoroutside circles 18 a and 18 b as shown in FIG. 5. These could be notches13 a and 13 b on the exterior of outer lamination 5. These notches couldfunction as a space for a recessed weld or space for cooling air torecirculate inside the machine.

FIG. 7 shows an entire motor assembly that includes the stator assemblyshown in FIG. 1. The rotor configuration is showing magnets 25 and tabpole plates 26 and 27. This rotor configuration is the same as shown inthe two U.S. patent application Ser. No. 13/438,792 entitled HIGHEFFICIENCY PERMANENT MAGNET MACHINE WITH SEPARATED TAB POLE ROTOR ANDSTACKED CERAMIC MAGNET SECTIONS and Ser. No. 13/438,803 entitled SHAFTATTACHMENT MEANS FOR HIGH EFFICIENCY PERMANENT MAGNET MACHINE WITHSEPARATED TAB POLE ROTOR both filed on Apr. 3, 2012, and eachincorporated herein by reference. Outer tube 6 is preferably shrunk fitonto outer lamination 5 to mechanically align as well as transmittorque. The outer tube is compressed between drive side endplate 28 andnon-drive side endplate 29 using threaded tie bars 30. The frictionbetween outer tube and endplates transmits the torque to the machinemounting features. Alignment of shaft 24 is controlled through outertube 6, endplates 28 and 29 and through bearings on each end. Sealing ofthe system can be accomplished by adding an O-ring seal 31 and 32 asshown in FIG. 8.

The inner coil 8 is shown in detail in FIG. 9. This coil is edge woundbecause the width of the wire is narrower than the thickness in thedirection the wire is bent around the stator tooth. When wire is bent ittends to form a keystone shape in the corner areas. As shown in FIG. 9,when wire is in shape of a rectangle 35 with the mandrel side 37 and theoutside edge 36, it forms a keystone shape 38 and the mandrel side 40grows in width and the outside edge 39 contracts in width. The fact thatwires always want to keystone when bent is why the coils bulge out inthe corners as shown by 34. Limiting the amount of the keystone isimportant for overall packaging and can be controlled in themanufacturing process if the right process is used. The coil shown istwo in hand wound (two wires wound simultaneously) with wires side byside 33. Depending on the specific design it may make sense to havesingle wire, two in hand or more than two in hand.

It is important for to have the wire thermally connected to the coolingmanifold 12 as shown in FIG. 10. The cooling manifold is electricallyisolated from the windings 8,9,10, 11, and by plastic insulator layer 41that functions as ground insulation. Each of the winding layers iscompressed towards cooling manifold 12. This is accomplished by wedgeassemblies 14 a,14 b,14 c;15 a,15 b,15 c; and wedge block 14 d whichpush the windings up against each other through insulators 16 a,16 b, 16c; against the insulation layer 41; and ultimately against coolingmanifold 12. The first wedge assembly functions by driving tapered wedge14 a and 14 b against each other in the cutout of 14 c. The second wedgeassembly functions by driving tapered wedge 15 a and 15 b against eachother in the cutout of 15 c against the wedge block 14 d. There is aslot liner insulation 42 that acts as ground insulation between thewires and the outer lamination 5. This insulation is not directly in thepath so thermal conductivity is not critical.

Insulators 41,16 a, 16 b, and 16 c are directly in the path of heattransfer so thermal conductivity is critical. Further, due to the higherheat fluxes generated with more compact machines of this type, thethermal conductivity is even more critical. This can be accomplished bysome combination of making it thin and using high thermal conductivitymaterial. It is desired to have at least a thermal conductivity of 1W/mK and preferably a conductivity of 3 W/mK and ideally a conductivityof 10 W/mK. Since this material also needs to be an electrical insulatorto act as primary insulation, metals typically do not work. To functionas primary insulation, electrical resistivity needs to be greater than1000 Ohm cm and preferably greater than 10̂15 Ohm cm. Plastics typicallyhave thermal conductivities less than 1 W/mK, but there are someplastics such as those made by Coolpoly in Rhode Island USA that achievethis combination of properties.

Materials such as Liquid Crystal Polymer (LCP) and Polyphenylene Sulfide(PPS) make good choices due to their heat stability, but need to havespecial fillers to achieve high thermal conductivity.

The wire layers are preferably pre-insulated to minimize the thermalinsulation with maximum electrical insulation. Wire is available withmany grades of insulation with one or multiple coated layers.Polyamide-imide and Polyester are common material used for some of theselayers with the Polyamide-imide typically as the outer layer to havegood abrasion resistance.

The coils are preferably individually wound and then connected togetherafter assembly. An assembly of the 4 coils and the plastic insulator isshown in FIG. 11. The inner coil 8 is electrically connected to the2^(nd) coil 9 at location 45 a and 45 b. This joint can be soldered,brazed or mechanically connected. The 2^(nd) coil 9 is electricallyconnected to the 3^(rd) coil 10 at location 44 a and 44 b. The 3^(rd)coil 10 is electrically connected to the 4^(th) coil 11 at location 43 aand 43 b. All 4 coils are therefore connected in series with thefunctional entire coil starting at location 46 on the first coil andending at location 47 on the 4^(th) coil. It is important to note thateach of the strands of the wire is individually connected for reducingeddy current losses. Also, the configuration shown causes the furthestradial member of one coil to be connected to the closest radial memberof the next coil. This is also done for eddy current reasons. Thisshould be done for at least one of the coil connections, but here isshown at all 3 coil connections.

It is possible to do similar connections with more or less than 4layers. In an alternative configuration, the coils can be connectedelectrically in parallel to reduce the size of wire required. If this isdone, it is important to match the impedance of the parallel coils.

Particular geometry of the winding is important to maximize the amountof wire that can fit in the slot and maximize the thermal conductivitybetween the wire and cooling manifold. To have the coils sit flat it isimportant to keep a configuration as shown in FIG. 12. The first wrap 48and 49 is planar with the other side of the first wrap 50 and 51. Thiswrap then crosses over 54 and 55 to the second wrap 52 and 53 on onlyone edge of the coil. The first side of the second wrap 52 and 53 isplanar with the other side of the second wrap 56 and 57. Ideally thiscrossover 54 and 55 is done on the same end of the coil as theterminations 63 and 64 are done. The keystoning of the bends causes thecoil to have bulges on the corners 58, 59, 60, 61, and 62. These bulgescan be accommodated since they are located axially beyond the statorlaminations. Bumps 65 can be added to the slot liner insulation 42 andBumps 66 can be added to insulation 41 on other side as shown in FIG.13.

The winding process to edge wind pre-insulated wire and minimizekeystoning in the corners is critical. As shown in FIG. 14 a rectangularwire 69 is clamped by clamp 71 to spindle 67 against mandrel 68. Widthis constrained by edge guide 70. Spindle 67, clamp 71, and edge guide 70are all fixed with respect to each other and rotate together. Thespindle is rotated in a clockwise direction as viewed from above to formwire around the mandrel. Preferably there would be controlled tension onwire end 72 during the bend as shown in FIGS. 14 and 15. This controlledtension allows the neutral bending plane location to be controlled. Moretension moves the neutral bending plane toward the mandrel 68. While thewire is being bent the wire is controlled between surfaces 74 and 75 asshown in FIG. 16. Fairly tight clearance should be maintained betweenthe wire and these surfaces to minimize keystoning. Note the edge guide70 that controls the wire along surface 75 extends at least past theneutral bending surface, approximately half way up the wire thickness.This bending is preferably done with pre-insulated wire to optimize theprocess. Additional bends can be made up unclamping the wire, rotatingthe spindle back to the previous position, extending the wire thecorrect amount, and then re-clamping the wire and repeating the process.When completing more than 360 degrees of bends, the wire can be guidedup to sit on top of (vertically up along axis of spindle) the wire beingbent. End termination, special features, and truing up the stack can becompleted once the winding is complete.

A very similar winding process can be used to edge wind multiple in handwires that are pre-insulated with minimizing keystoning in the corners.As shown in FIG. 17, two in hand rectangular wire 78 is clamped by clamp80 to spindle 76 against mandrel 77. Width is constrained by edge guide79. Spindle 76, clamp 80, and edge guide 79 are all fixed with respectto each other and rotate together. Spindle 76 is rotated in a clockwisedirection as viewed from above to form wire around mandrel. After it isbent 90 degrees the wire 69 would now be bent as shown in FIG. 15.Preferably there would be controlled tension on wire end 81 during thebend as shown in FIG. 17. This controlled tension allows the neutralbending plane location to be controlled. More tension moves the neutralbending plane toward the mandrel 77. While the wire is being bent thewire is controlled between surfaces 83 and 84 as shown in FIG. 18.Fairly tight clearance should be maintained between the wire and thesesurfaces to minimize keystoning. Note the edge guide 79 that controlsthe wire along surface 84 extends at least past the neutral bendingsurface, approximately half way up the wire thickness.

The overall process of building this stator assembly consists of

-   -   1) Creating the edge wound coil as described above,    -   2) Assembling the tooth assembly that consists of multiple edge        wound coils, cooling manifolds, laminated teeth, and electrical        insulation in various locations,    -   3) Compressing the wires together and against the cooling        manifolds and holding them together in a fixture,    -   4) Inserting this assembly into the lamination stack including        driving wedges to lock teeth into the stator lamination and        driving wedges to push wire tight against cooling manifolds,    -   5) Any required fluid or electrical interconnections that are        completed prior to Vacuum Pressure Impregnation (VPI),    -   6) Vacuum Pressure Impregnation (VPI) of the stator assembly.

1. A rotary electric machine comprising a stator having a circumaxiallyspaced series of axially extending discrete teeth defining a similarseries of circumaxially spaced winding slots therebetween, a pluralityof stator coils at least partially disposed respectively in the slots,each of said stator coils being configured and wound as a concentratedwinding, wherein windings are comprised of at least two generallyconcentric coils that are of edge wound construction.
 2. A rotatingelectric machine as set forth in claim 1 wherein a cooling manifold islocated between said teeth and said windings.
 3. A rotating electricmachine as set forth in claim 2 wherein there is at least one pair ofwedges that compress the windings against the cooling manifold.
 4. Arotating electric machine as set forth in claim 2 wherein the insulationlayer between the cooling manifold and the winding is at least partiallycomprised of material that has a thermal conductivity of at least 1W/mK.
 5. A rotating electric machine as set forth in claim 1 whereineach of the coils is built as a separate unit and then electricallyconnected together in the assembly.
 6. A rotating electric machine asset forth in claim 5 wherein wire is wound at least two in hand andconnections between adjacent coils are made separately on each wirestrand and insulated from each other.
 7. A rotating electric machine asset forth in claim 1 wherein the wire in insulated prior to bending. 8.A rotating electric machine as set forth in claim 1 wherein theinsulation contains at least one layer of polyamide-imide.
 9. A rotatingelectric machine as set forth in claim 1 where for said coils, the wireon 3 sides of each turn are generally planar for at least some of theturns on said coil.
 10. A rotating electric machine as set forth inclaim 1 wherein rigid insulators are provided and incorporate featuresthat accommodate wider coils in the corners than in the slot.
 11. Arotating electric machine as set forth in claim 1 wherein at least someof the coils are connected electrically in parallel.
 12. A rotatingelectric machine as set forth in claim 2 wherein said cooling manifoldincorporates a step that approximately the same height as the thicknessof one coil layer.
 13. A rotating electric machine as set forth in claim1 wherein at least one layer of insulation with a thermal conductivityof at least 1 W/mK separates edge wound coils.
 14. A method for buildingedge wound coils from wire that is pre-coated with electricalinsulation, said method consisting of clamping wire into a spindleassembly comprising a spindle, edge guide and clamp that constrain thewidth of the wire; and then rotating the spindle; edge guide; and clampat the same time to create a bend in the wire.
 15. A method for buildingedge wound coils as set forth in claim 14 wherein said wire consists oftwo or more strands of rectangular wire adjacent to each other.
 16. Amethod for building edge wound coils as set forth in claim 14 whereinwire tension is controlled while the spindle rotates.
 17. A method forbuilding stator assemblies from rectangular wire that consists ofmanufacturing a plurality of edge wound coils by clamping wire into aspindle assembly that constrains the width of the wire, rotating thespindle assembly to create a bend in the wire and repeating as manytimes as necessary; and nesting said coils inside each other as well asinserting cooling manifolds and stator teeth inside coils; clampingcoils to nest tightly against said cooling manifolds; then inserting thewinding assembly into the stator outside lamination and securing inplace; completing any mechanical, fluid and electrical interconnectionsthat are to be done before vacuum pressure impregnation, and then vacuumpressure impregnation of the stator assembly.
 18. A method for buildingedge wound coils as set forth in claim 17 wherein the wire consists oftwo or more strands of rectangular wire adjacent to each other.
 19. Amethod for building edge wound coils as set forth in claim 17 whereinwire tension is controlled while the spindle rotates.
 20. A method forbuilding edge wound coils as set forth in claim 17 wherein said wire ispre-coated with electrical insulation.
 21. A method for building edgewound coils as set forth in claim 17 wherein the coils are compressedtogether with wedges after insertion into the outside lamination.
 22. Amethod for building edge wound coils as set forth in claim 17 whereinsecuring in place of said winding assembly consists of driving at leastone set of wedges in place.